Variable indicator light cap



ad'u llfd April 1945. A. D. DIRCKSEN EIAL 2,372,937

VARIABLE INDICATOR LIGHT CAP Filed Oct. 28, 1942 ARNOLD D- D/RC/(SE'N CECIL BARDWELL JESS c. ROSE mvsm'ons Patented Apr. 3, 1945 UNITED STATES Hui-ll Mi! 1 'iUUll PATENT OFFICE VARIABLE INDICATOR LIGHT GAP California Application October 28, 1942, Serial No. 463,712

2 Claims.

This invention relates generally to warning and indicator lamps, and more particularly to variable light caps for small sized warning or indicator lamps of the instrument panel type.

Indicator r warning lamps of the type mentioned are frequently installed in situations in which they may sometimes be used in the daylight, and sometimes in darkness. If suflicient light is emitted that the lamp is easily observed in daylight, it is then so bright in darkness as to detract from the observer's dark eye adaptation. For instance, if the observer is a pilot of an aircraft, it is highly important that his dark eye adaptation be preserved, and it is therefore im- Dortant that any indicator lamps on his control panel be substantially dimmed. On the other hand, if the lamp be sufliciently dimmed for night time use, it is then too dim for observation in daylight.

It is the object of the present invention to provide a simple and improved easily adjustable dimming cap for an indicator lamp.

The invention will be best understood from the following detailed description of certain present illustrative embodiments thereof, reference for this purpose being had to the accompanying drawing, in which:

Fig. 1 .is an enlarged elevation of a warning lamp in accordance with the invention, parts being broken away;

Fig. 2 is a still further enlarged section on line 2-2 of Fig. 1;

Fig. 3 is a section on line 33 of Fig. 2;

Fig. 4 is a section on line 4-4 of Fig. 2;

Fig. 5 is a detail side elevation of the stationary shutter disk; and

Fig. 6 is a view showing a modified arrangement, in which the variable light cap is mounted separately of the lamp.

In the drawing, numeral |0 designates generally a lamp housing, comprising an externally threaded barrel H and an enlarged cylindrical head l2, the housing being provided with a central bore l3 for reception of the lamp bulb I4 and other parts presently to be mentioned. Preferably, the forward end of bore |3 meets with a conical portion or opening l5 formed in the forward side of head l2, so as to form a conical reflector surface. Lamp bulb I4 is mounted within bore |3 in any suitable or usual manner, as for instance by means of cement such as indicated at IS.

.A flanged insulator bushing I1 is inserted within the rearward end of bore l3, the flange l8 of said bushing engaging the rearward end of barrel II, and inserted within bushing I1 is a flanged contact button 20, the flange 2| of which engages the flange |8 of insulator bushing H. The filament 22 of bulb I4 is connected to barrel II by wire 23, and to contact button 20 by wire 24. It will of course be understood that the screwthreads Ila on the exterior of barrel II are adapted for connection with a suitable socket, and that the contact button 20 at the end of the barrel is adapted to make electrical contact with a suitable contact member contained in such socket.

Rotatably mounted on cylindrical head I2 is a rotating shutter cap 30, comprising a front wall 3| and a rearwardly extending, cylindrical side wall 32 rotatably fitted onto head l2. Wall 3| is formed with a depressed, annular seat 36 for a translucent, colored, or cloudy lens 31, which may be retained in place in any suitable or usual manner. The wall portion below lens 31 is formed with shutter apertures 38, here shown as two in number, and of sector shape, being positioned on opposite sides of center, as clearly appears in Fig. 3. A very small light-passing aperture 39 may also, if desired, be provided at the exact center.

Confined between head l2 and wall 3| of rotating shutter cap 30 is a stationary shutter disk 4|], one side of which is formed with a downwardly bent lug 4| which engages in a seating notch 42 formed in the side of head I2 to secure the shutter disk against relative rotation with respect to head l2. Shutter disk 40 is preferably formed with two downwardly bent leaf springs 44, which press downwardly against the head l2, and press the shutter disk upwardly against the underside of wall 3| of the rotating cap, thus maintaining the shutter disk 0 in light-tight engagement with wall 3|, and also supporting these two parts at selected setting against displacement due to possible vibration.

The stationary shutter disk 40 is provided with two shutter apertures 45, shaped and positioned similar to apertures 38 of cap 30, and preferably, with a centrally located light passing aperture 46, of the same size as aperture 39 and in line therewith.

A stop pin 50 set into and projecting radially a short distance from the side of head I! engages in a ninety degree circumferential slot 5| I formed in the side 32 of cap 30, this pin serving not only to limit rotation of cap 30 with reference to head l2, but also securing the cap on the head. With cap 30 turned so that one end 01' its slot 5| is in engagement with pin 50, shutter apertures 38 and 45 are in full registration. and with cap 30 so turned that the other end of its slot is in engagement with pin 50, the apertures 38 and 45 are entirely out of registration. In the former position, a maximum of light directly from lamp l4, and reflected from surface I5, is passed through the shutter apertures and transmitted through lens 31, while in the latter position, all light is out 01f excepting for that passing through the aligned central apertures 39 and 46. The light may be adjusted to any value in between by rotative adjustment of the cap between these two extreme positions. For this pur pose, the cap is designed for convenient manipulation by the fingers, and is preferably formed with a knurled side surface, as indicated at 32a in Fig. 1, to facilitate this adjustment operation.

If the aligned, central light apertures 39 and 46 are employed, the light can never be completely out off, excepting by operation of a switch. This provides a minimum amount of light for night operation. These always-open apertures may of course be omitted, if it should be desired to provide for complete extinguishing of the light by means of the shutter cap.

Fig. 6 shows a modification, in which the shutter cap and lamp are separately mounted. Number 60 designates an instrument panel provided with a projecting tubular boss 6|. The shutter cap 30, which may be identical with the shutter cap 30 of the preceding figures, is rotatably mounted on tubular boss 6| in a manner identical to the mounting of cap 30 of Figs. 1 to 5 on the head l2 of lamp housing [0, as will be evident. The stop pin 5la for the cap is in this instance set into the wall of tubular boss 6| and the downwardly bent stationary shutter lug 4la is recessed into boss Bl, all as will be entirely clear from an inspection of Fig. 6. The lamp bulb 62 is separately mounted, in any suitable socket, not illustrated, directly below and in alignment with the tubular boss 6|. 1

It will be understood that the drawings and description are for illustrative purposes only, and that various changes in design, structure and arrangement may be made without departing from the spirit and scope of the invention or of the appended claims.

We claim:

1. In combination, a cylindrical member formed with a central opening, a cap rotatably mounted on said cylindrical member, said cap comprising a front end wall member and a cylindrical side wall flange portion extending rearwardly therefrom rotatably fitted on said cylindrical member, a shutter disk fixed against rotation relatively to said cylindrical member positioned parallel and adjacent to said front end wall member of said cap and between said end wall member and said cylindrical member, spring leaves formed as a part of and bent out of the plane of said shutter disk acting against said cylindrical member to press said shutter disk against said front wall member of said cap, and means securing said cap on said cylindrical member against the pressure of said spring leaves, said shutter disk and said front end wall member of said cap having shutter apertures adapted to be moved into and out of register with one another by relative rotation of said cap on said cylindrical member.

2. In combination, a cylindrical member formed with a central opening, a cap rotatably mounted on said cylindrical member, said cap comprising a front end wall member and a cylindrical side wall flange portion extending rear wardly therefrom rotatably fitted on said cylindrical member, a shutter disc fixed against rotation relatively to said cylindrical member positioned parallel and adjacent to said front end wall member of said cap and between said end wall member and said cylindrical member, spring leaves formed as a part of and bent out of the plane of said shutter disc acting to cause a friction to be exerted on said front wall member of said cap, and means securing said cap on said cylindrical member against the pressure of said spring leaves, said shutter disc and said front end wall member of said cap having shutter apertures adapted to be moved into and out of register with one another by relative rotation of said cap on said cylindrical member.

ARNOLD D. DIRCKSEN. CECIL BARDWELL. JESS C. ROSE. 

